METHODOLOGY: A retrospective study of all positive Streptococcus pneumoniae isolates consistent with invasive disease from children below 14 years of age hospitalised in two tertiary hospitals; between year 2012 and 2016 was conducted. IPD cases were defined as isolates of S. pneumoniae from a normally sterile body fluid site.
RESULTS: Fifty-four patients were identified in both centres, 35 (65%) from HRPB as compared to 19 (35%) from HS. Majority of cases (14/35, 40 %) in HRPB were of Orang Asli in comparison to Malay children (16/19, 84%) in HS. Septicaemia, pneumonia and meningitis were the most common clinical presentation of IPD in both centres. There was a noticeably higher percentage of isolates found to be non-susceptible (NS) in HS (62.5%) as compared to HRPB (37.5%) although of no statistical significance. Mortality rate was higher in HRPB (26%) in comparison to 11% in HS.
CONCLUSION: This study highlighted the varied presentation of IPD in two different hospital settings. Although both deemed as urban centres, this study emphasises the importance of understanding socio-demography, health facility availability and primary care practices as it significantly alters the clinical course of a disease.
METHODOLOGY: One hundred and twenty clinical isolates of S. pneumoniae were obtained from patients of University Malaya Medical Centre (UMMC). The strains were screened using a multiplex real-time PCR method for the presence of alterations in the genes encoding the penicillin binding proteins: pbp2b, macrolide resistance determinant ermB and the pneumolysin gene, ply. Dual-labelled Taqman probes were used in the real-time detection method comprising three different genes labeled with individual fluorophores at different wavelengths. One hundred and twenty isolates from bacterial cultures and isolates directly from blood cultures samples were analyzed using this assay.
RESULTS: A multiplex PCR comprising the antibiotic resistance genes, ermB and and pneumolysin gene (ply), a S. pneumoniae species specific gene, was developed to characterize strains of S. pneumoniae. Out of the 120 pneumococcal isolates, 58 strains were categorized as Penicillin Sensitive Streptococcus pneumoniae (PSSP), 36 as Penicillin Intermediate Streptococcus pneumoniae (PISP) and 26 as Penicillin Resistant Streptococcus pneumoniae (PRSP). All the 58 PSSP strains harboured the pbp2b gene while the 36 PISP and 26 PRSP strains did not harbour this gene, thus suggesting reduced susceptibility to penicillin. Resistance to erythromycin was observed in 47 of the pneumococcal strains while 15 and 58 were intermediate and sensitive to this drug respectively. Susceptibility testing to other beta-lactams (CTX and CRO) also showed reduced susceptibility among the strains within the PISP and PRSP groups but most PSSP strains were sensitive to other antibiotics.
CONCLUSION: The characterization of pneumococcal isolates for penicillin and erythromycin resistance genes could be useful to predict the susceptibility of these isolates to other antibiotics, especially beta-lactams drugs. We have developed an assay with a shorter turnaround time to determine the species and resistance profile of Streptococcus pneumoniae with respect to penicillin and macrolides using the Real Time PCR format with fluorescent labeled Taqman probes, hence facilitating earlier and more definitive antimicrobial therapy which may lead to better patient management.